Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
Isolation structures provide for electrical isolation between devices in the wafer. In metal interconnect structures, one or more openings may be formed in metal layers and then filled with a low-k dielectric material using spin-on-dielectric (SOD) technology, as an example. The low-k dielectric material may help to electrically isolate various features of the meal interconnect structures from each other.
Due to the large numbers of devices that are present on a semiconductor substrate and the continual increase in the integration density of various electronic components (e.g., transistors, diodes, resistors, capacitors, etc.) by continual reductions in minimum feature size, the space between the devices is getting narrower. Because of this, isolation of the devices from each other is becoming increasingly difficult. For example, in high aspect ratio openings it is becoming difficult to uniformly deposit the dielectric material in the openings, leading to voids being formed in the dielectric materials. Such voids adversely affect isolation of the devices which may in turn affect the overall structural integrity of the integrated circuits.